The crop lifter is employed on a vegetable harvester to lift plant material, that has been severed from the ground, and deposit the plant material on an elevating conveyor.
Vegetables which grow on vines and bushes such as cucumbers, zucchini and squash have heavy green foliage and heavy dense fruit. The fruit can be harvested by hand or by mechanical harvesters. When the fruit is harvested by hand, the harvest involves manually removing fruit as the fruit reaches the desired size and ripeness. For some crops, fruit is removed from a given plant a number of times. The period of time between the first removal and the last removal can vary from several days to a number of weeks. The fruit of a few crops can be harvested over most of an entire growing season.
Fruit picked by hand is generally relatively expensive. Some vegetables are highly desired and customers will pay a premium price. Other vegetables will not command a premium price. For vegetables that will not be purchased at a premium price, people can grow them in their gardens or they can be harvested by mechanical harvesters. Cucumbers, for example, are generally harvested by mechanical harvesters. These harvesters are whole crop harvesters that remove the entire crop in one pass through the field. Such harvesters remove some fruit that is too mature or too large as well as fruit that is immature and too small. The fruit that is too mature as well as the fruit that is immature is discarded. Mechanical harvesters reduce the cost of harvesting by machine over the cost of hand picking by a sufficient amount to more than offset the losses due to discarding fruit that is too mature and fruit that is immature.
Grain crops such as barley, flax, dry beans, and wheat are frequently severed from their roots and left on the ground to dry for a few days. After these crops dry, they are picked up with a pick-up attachment on a grain harvester, thrashed and cleaned. The stocks, leaves and foliage are dead, dry and lightweight. The seeds are also dry. Due to the dryness and the relatively light weight, such crop material is easy to lift off the ground and convey into a harvesting machine.
Vegetable crops are generally harvested before the plant or the fruit lose an appreciable portion of their water content. Cucumbers for example that have remained in the field and lost a significant portion of their total water content are no longer suitable for human consumption. It is therefore necessary to gather such fruit and transport it to a processing facility as soon as possible after the plant has been severed from the ground.
Vegetable harvesters, that remove the whole crop from the ground, often have blades that separate plants and fruit from their root systems. A conveyor directly behind the blade or blades, that lifts the plant material from the ground, elevates the plant material and delivers the plant material to a cleaning station and to a fruit separation station. The heavy wet crop material and fruit tends to be pushed forward by the conveyor before it is lifted up onto the conveyor. As a result some fruit is damaged and some fruit is lost. The quantity of dirt, rocks and old crop residue conveyed into the harvester is increased.
U.S. Pat. No. 4,965,993 discloses a vine gripping convey that clamps some leaves and vines between pinch bars, elevates and carries the crop material on the upper run of a main conveyor. The pinch bars lift some crop material and drag other crop material up onto the main conveyor. This has reduced losses and permitted an increase in the ground speed of the harvester thereby increasing harvester capacity. The pinch bars must move down below the tops of the vegetation to engage and grasp leaves and vines. As pinch bars move down into the vegetation they tend to force some leaves, stalks and vines downward where they cannot be clamped between two bars. In some crop conditions the vines remain relatively close to the ground and most of the leaves remain relatively close to the ground. In these conditions, the pinch bars cannot engage large quantities of crop material and provide only minimal assistance in conveying crop material onto the main conveyor.
The crop lifters include a disk on each side of a row of plants. Each of these disks rotate about an axis that extends from positions to the side of a plant row inward toward the plant row, forward in the direction of movement and slightly upward from horizontal. Two adjacent disks on opposite sides of a row of plants form a crop lifter. The disks of a crop lifter diverge to the front and upward from their centers. The radially outer portions of each pair of the disks make contact with each other below their hubs and to the rear of their hubs. In this position the two adjacent hubs move crop material inward toward the center of a row, clamps crop material between the two adjacent disks and lift the crop material. The two disks move out of contact with each other at or slightly below the height of their hubs and to the rear of their hubs. As the disks separate, vegetation that was lifted is dropped onto the upper portion of the forward end of the main conveyor.
The pairs of adjacent disks that rotate about axes that intersect at a point midway between the two disks, forward of the disk centers and above the disks axes can be driven by the crop material and forward movement of the harvester. The disk could also be positively driven if desired.
The crop lifters for a row of plants can also include two disks that are spaced apart and mounted on a horizontal transverse shaft. The horizontal transverse shaft is driven. Both of the disks are made from flexible material. Closure arms force the rim portions of the flexible disks together behind and below the axis of the driven shaft. Contact between the rims occurs for up to 35xc2x0 about the axis of the driven shaft.